How to connect internal LVDS to LCD

[RyzenMaster.sys]

Hello. I am working on a project creating a custom AIO computer built around a monitor

I have an AEON EMB-H61A ITX motherboard which features an internal LVDS display connector, plus a single 12v input, which would make it ideal for this project.
The motherboard in question: https://www.aaeon.com/en/p/mini-itx-emb-h61a

DISPLAY I/O

LVDS connector x 1, LVDS Power select jumper x 1, LVDS Brightness Control Type Selection x 1, LVDS Panel Backlight Power Selection x 1, LCD_POWER 5 pin connector x 1

This LVDS connector on this motherboard is a 30 pin non ribbon connector. I believe the LCD power connector and jumpers are in the upper right panel.

Can anyone point me in the right direction of how to connect this to a normal LVDS LCD panel? The LVDS connector on this board does not match ANY of the laptop nor desktop monitor LVDS LCDs ive looked at. I assume the 5 pin is for powering a backlight, but am not sure what type of LCD would use this connector.

 

[LabRat 891]

You have my attention.
This kind of project has been on my list to attempt for over a decade. I have at least 2 motherboards with LVDS output too. I've got about 0 idea how to connect and make 'em work.

I have played with 'control boards' purpose-flashed to be compatible with certain laptop LCDs, however. I assume there's some kind of firmware or manual settings that must be set for the motherboard to properly control the LCD.

 

[RyzenMaster.sys]

Documentation is key!

After some more digging, the manual, not the datasheet was what I needed.

The 5 pin is for powering an inverter to power the panels backlight. This can either control straight DC or PWM mode. It can either output 5 or 12v to the inverter depending on jumper placement. I changed it from 5v to 12v since most backlight inverters I see require more than 5v.

There is a jumper for the LVDS to set the LVDS panel voltage to either 3.3 or 5v as well. I did not know LVDS panels had different voltages they operated on.

I am not sure how to control things such as resolution or refresh rate etc, but I assume it will auto detect this.

 

[LabRat 891]

link to your motherboard's manual

Okay, looks like the manual will be your friend. There appear to be jumpers to set the LVDS driving voltages and backlight type

J1 LVDS Panel Voltage Selection

J1 Function 1-2 +5V 2-3 +3.3V (Default)

J2 Inverter Voltage Selection

J2 Function 1-2 +12V 2-3 +5V (Default)

J3 Mode Selection for Back Light Control of Inverter

J3 Function 1-2 DC Voltage Control (Default) 2-3 PWM Control

Beyond the jumpers, there's some configurations that must be set in BIOS
3-26 onwards in your manual covers the configuration options: link to manual

The manual should also list what kind of cables you need. If not, you can eBay search for a 30-pin LVDS and LCD power cable that matches the physical configuration of your motherboard's connector and the LCD of choice.

@RyzenMaster.sys The resolution and bit-depth are set in BIOS. I'm assuming there will be limitations on compatible displays, based upon the limit of options presented here.

 

[RyzenMaster.sys]

The monitor I have settled on is a 4 year old BenQ GW2270. It has a very good panel, but mine has an issue with the controller board that means it usually shows the BenQ logo but won't detect input on either the DVI or VGA. It sometimes detects and displays but cuts out randomly. Seems like a perfect candidate for this.

The panel it uses is this:

AUO T215HVN01.1 Overview - Panelook.com

AUO T215HVN01.1 datasheet 6 files, stocks, price, suppliers, photos, compatible models. Specs: a-Si TFT-LCD, 21.5', 1920×1080, 250 nit, 3000:1 (Typ.), 16.7M color, 60Hz, WLED, LVDS (2 ch, 8-bit)

www.panelook.com

It appears to use 30 pin 5v LVDS.

Any clue if the backlight would need DC or PWM dimming?

The cable listed in the manual for LVDS is a specific one from an OEM but I can't find it online.

FIX-30Pin 2ch 8bit LVDS Cable for 17inch~26inch LCD Panel 8 Bits 25cm/250mm M | eBay

Suitable for LCD display with 2ch LVDS interface (RGB 8-bits data, 10 pairs of differential signal; Type Part Number: JAE FI-XB30SSL-HF15);. LVDS ODD 0 - Signal. LVDS ODD 0 + Signal. LVDS ODD 1 - Signal.

www.ebay.com

I'm thinking this will do

 

[LabRat 891]

Full Datasheet
The nomenclature for the LED backlight in the Datasheet indicates an expectation of PWM power supply. This would also be 'standard' for LED lighting devices in general (as opposed to CCFLs).
Important Edit-in: Seems AUO leaves DC (assuming ="Analog Dimming") vs. PWM up to the designer of the backlight driver/final product.

Note 4-6: AUO strongly recommend “Analog Dimming” method for backlight brightness control for Wavy Noise Free. Otherwise, recommend that Dimming Control Signal (PWM Signal) should be synchronized with Frame Frequency

(Tangential commentary [best ignored, for now]: So, does that mean PWM @ a multiple of 60hz then? AFAIK default 'base frequency' for PWM is 40khz [or 666.666666666666~ * of 60hz])


However, I don't think the backlight gets connected directly to your mobo; the Voltage Spec for the LED backlight is far too high.
Panelook.com also notes that it requires and external backlight-driver, and the options on your motherboard for backlight power do not match the panel's specs, whatsoever:

Input Voltage

46.5/51V (Typ./Max.)

I'd Ass-U-Me that you'll need to salvage the backlight-driver out of the original display. (Hopefully, it's separate and not integral to the display's mainboard)

 

[RyzenMaster.sys]

I think I could use an inverter similar to this. I think the 5 pin connector on the motherboard is meant to power one.

https://www.ebay.com/itm/202737180710 something like this inverter to take the brightness signal and 12v DC from the 5 pin on the motherboard and use it to power the LCD

The backlight driver board from the BenQ is still salvageable, however I would imagine needs connected to the LCD control board in order to get a signal to turn on and the brightness of the backlight. Not sure if I could somehow connect that to this motherboard or not.

 

[LabRat 891]

I think I could use an inverter similar to this. I think the 5 pin connector on the motherboard is meant to power one.

https://www.ebay.com/itm/202737180710 something like this inverter to take the brightness signal and 12v DC from the 5 pin on the motherboard and use it to power the LCD

I do see a claim of "auto-adjustment", but that 88V stated Vout scares me. The Panel's spec is max 51V.
I'd need to better understand how it auto-detects/adjusts. I mean, it could be an instantaneous and passive feature based off resistance or series-circuit diode vDrop. I'm not that educated in EE (yet) to even feel remotely safe making an assumption one way or another.
To be safe, in my position, I'd try and find something more purpose-built. Something specifically salvaged from another 'compatible' application. (I can't imagine this panel is the only LCD w/ 46.5V-51V LED arrays)


I'm kinda hoping someone that's had experience building 'purpose-built display-integral PCs' pops in and tells us the ins-and-outs going on here. Those LVDS connectors are there for 'industrial' and 'commercial' appliance PCs. (Think: interactive retail signage and scratch-built manufacturing machines.)

 

[RyzenMaster.sys]

I'll have to check on what connectors the backlights use on that panel when I tear it apart again tomorrow.

This is the connector used for the backlight on the BenQ monitors panel

 

[Bill_Bright]

I am curious as to why you are calling this an AiO computer?

A true AiO computer is essentially a laptop motherboard integrated and mounted inside a large monitor case. The cables, including the video cable (but not the keyboard or mouse cable) and drives are also mounted inside the monitor case. As are the computer speakers, mic and headphone jacks too. And there is just one power supply that supports the motherboard and monitor and everything else. This is why they are called "All IN One" computers.

Unless you are also building a custom monitor case and planning on mounting this ITX motherboard, drives, and the monitor (and necessary cooling) into that custom monitor case, what you are doing is building a mini-ITX computer - an admirable task I sure am not trying to diminish.

I am just saying, it should be called what it is.

Now if you are building a custom monitor case to house "all" the components, I sure would be interesting in hearing your plans for that too.

 

[RyzenMaster.sys]

The plan is indeed for it to all be "All in one". I intend to reuse as much of the original structure as I can, with extensive modification. I will have to figure out how the case will be designed AFTER I get it all connected and situatited. Possibly 3d printed or something otherwise custom.

Video, LCD power, and backlight inverter 12v supply will be internal fed from the LVDS and inverter power headers on the motherboard directly to the LCD.

As far as powering it all, the ITX board is 12VO. The board just needs a 12v input, and it generates the 3.3v and 5v onboard, maning this all will work on a single 12v input.

Power will likely will be an external laptop style 12v PSU. Most aios work this way anyhow.

As far as speakers? I am not too concerned about implementing them in my design so far. Can be added later perhaps. This monitor doesn't have speakers I can use, but I could find some laptop speakers and figure out some way to use them later.

Storage can be handled by the msata port on the motherboard, however 2.5in is a possibility as the board has a header where a break out SATA power cable can connect, and it does have 2 SATA data ports.

Oh as far as cooling, the board does not have a standard mount and includes a cooler. A small aluminum thing that is no taller than the Io itself. I believe I can use a blower fan to cool it, rather than the downdraft design it's intended for.

 

[Bill_Bright]

The plan is indeed for it to all be "All in one". I intend to reuse as much of the original structure as I can, with extensive modification. I will have to figure out how the case will be designed AFTER I get it all connected and situatited. Possibly 3d printed or something otherwise custom.

Then, as with LabRat - you have my attention too. I can see how this would be a challenging, but fun project. I wish you luck and please keep us posted.

How are you planning on feeding the video to the monitor?

 

[RyzenMaster.sys]

How are you planning on feeding the video to the monitor?

That is the main point of this thread. I don't have it all figured out, but here is basically a summary.

LVDS is an internal video connector that is used by many devices. Think a video standard like HDMI, but the cable only ever will be run within a device, never outside.

Many (older) laptops have an LVDS connector on the motherboard which plugs directly into the LCD by a cable.

Many (older) desktop monitor LCDs also use LVDS connector. There is just a board that converts an input like HDMI to LVDS and sends it to the LCD. In this montior, this board is malfunctioning, hence why it was chosen.

Similar to a laptop board, this ITX motherboard has an LVDS connector. The desktop monitors LCD also has an LVDS input, so I will connect the LVDS on the motherboard to the LVDS input on the panel. I just need the appropriate cable.

It has jumpers and bios settings in order to change settings for the LVDS connector. I set 1080p in the bios.

Info on what LVDS is

Low-voltage differential signaling - Wikipedia

en.m.wikipedia.org

LVDS is older and mostly replaced by eDP and other standards anymore though.

This I believe is the cable I'll buy.

FIX-30Pin 2ch 8bit LVDS Cable for 17inch~26inch LCD Panel 8 Bits 25cm/250mm M | eBay

Suitable for LCD display with 2ch LVDS interface (RGB 8-bits data, 10 pairs of differential signal; Type Part Number: JAE FI-XB30SSL-HF15);. LVDS ODD 0 - Signal. LVDS ODD 0 + Signal. LVDS ODD 1 - Signal.

www.ebay.com

Very rough mock up of what I want to do

Did some measurements and the original "frame" and plastics aren't going to work, the boards up is like 1/8 inch too thick.

 

[Bill_Bright]

I guess my concern with feeding the video to the monitor is EMI/RFI shielding. With a laptop, the monitor, of course, flips up and away from the other electronics. And in most cases, that cable is pretty short too. I have only opened up one AiO an it had a large metal shield between the display and the board and the video cable was routed away, as much as possible from other cables and devices. IIRC, it was also shielded. Being digital (vs analog) will surely help mitigate, but not eliminate interference issues.

I think if me, I would look for a shielded cable - similar to this one.

 

[RyzenMaster.sys]

Did not think about shielding. That's good advice, thanks.

As far as chassis, the panel has screw holes that I can use to mount it.

Gonna make a box for it. But I want to get all the electronics situated first.

Robbed a fan from my laptop for test fitting. That works perfectly

I do see a claim of "auto-adjustment", but that 88V stated Vout scares me. The Panel's spec is max 51V.
I'd need to better understand how it auto-detects/adjusts. I mean, it could be an instantaneous and passive feature based off resistance or series-circuit diode vDrop. I'm not that educated in EE (yet) to even feel remotely safe making an assumption one way or another.
To be safe, in my position, I'd try and find something more purpose-built. Something specifically salvaged from another 'compatible' application. (I can't imagine this panel is the only LCD w/ 46.5V-51V LED arrays)


I'm kinda hoping someone that's had experience building 'purpose-built display-integral PCs' pops in and tells us the ins-and-outs going on here. Those LVDS connectors are there for 'industrial' and 'commercial' appliance PCs. (Think: interactive retail signage and scratch-built manufacturing machines.)

I sent this message to the seller of this:
https://www.ebay.com/itm/284804278255
"Hello. I would like to use this with an AUO T215HVN01.1 LCD which states 51v maximum for the backlight. Your product description says 75v output but "voltage is automatically adapted." Can you explain how this works and if this product will work with my LCD?"

There is some critical information that I am missing about how backlights work that would explain this I'm sure.